Plate glass polishing block



FEB. 6, R A MlLLER PLATE GLASS POLISHING BLOCK Filed June 16, 1930 2 Sheets-Sheet 1 Feb. 6, 1934. R. A. MILLER PLATE GLASS POLISHING BLOCK 1930 2 Sheets-Sheet 2 Filed June 16 INVENTOR www/LW Patented Feb. 6, 1934 UNITED STATES PATENT OFFICE PLATE GLASS POLISHING BLOCK Pennsylvania Application June 16, 1930. Serial No. 461,379

1 Claim.

The present invention relates to polishing blocks for use in surfacing plate glass, and constitutes an improvement on the polisher block of my pending application, Serial No. 394,075. Like the construction of said application, the present block is provided with an annular chamber carrying a liquid and serving to overcome the tendency of the block to tilt under the action of centrifugal force. The present invention has for its principal objects, the provision of an improved form of annular chamber designed to reduce the tendency of the block to rotate; the provision of a block having improved means for securing the felt to the bottom of the block; and the provision of a construction permitting the central portion of the block which is subject to wear to be replaced so that the major portion of the block can be used for an indefinite period. Certain embodiments of the invention are illustrated in the accompanying drawings, wherein:

Figure 1 is a vertical section through one of the improved blocks and the end of the spider arm which carries such block. Fig. 2 is a section on the line II-II of Fig. 1. Fig. 3 is a vertical section through a modification. And Figs. 4 and 5 are horizontal sections through modifications.

Referring to the drawings, 1 is an arm of the spider or runner which is suitably driven, as ini dicated in my application heretofore referred to;

2 is the spindle of the block; and 3 is the polisher block to which the invention particularly relates. The spindle 2 is of any approved construction and is mounted for rotation in the bearing 'I 4 carried by the end" of the arm 1. The lower y termediate the lugs 12, 12, 12 (Fig.' 2) and clamped in position by means of the ring 9. The central portion of the felt is cut away and bent up into the opening through the disc 6 where it is secured in position by means of the block 10. j This gives a very secure support for the felt and increases its period of usefulness as compared with a felt which has no holding means at its center as in the ordinary construction now universally used.

Access is given to the chamber 7 through openings which are closed by the plugs 13. This chamber is partially lled with a liquid such as water or mercury. In the use of the block on the spider arm 1, centrifugal force carries the liquid to the side of the block remote from the center of rotation of the spider so that in effect the center of gravity of the block is moved outward, thus giving increased pressure between the outer side of the block and the glass sheet 14 therebeneath, the function accomplished being more fully stated in my application heretofore referred to. The amount of counterbalancing effect as secured by the liquid under these conditions can be easily regulated by the amount of water or other liquid which is placed in the chamber '7. This may be regulated so that in operation the pressure throughout the entire face of the felt isuniform, or so that more pressure is exerted upon the glass by the outer side of the block than by the inner side. In order to reduce the movement of the liquid around the center of the block, the outer wall of the chamber 7 is preferably provided with the radially directed bales 15 (Fig. 2). The use of these baiiies tends to reduce the tendency of the block to rotate about its axis during the polishing operation.

Fig. 4 illustrates a modification in which the baiiies 16 are of a different shape, while Fig. 5 illustrates a construction in which no bailies are employed, these constructions being in other respects similar to that of Figs. 1 and 2.

The block 10 which clamps the central portion of the felt and receives the lower portion of the ball 5 is secured to the block 11 by means of the bolts 17, 17, whose heads lie in the slots 18, 18 in the disc 6. The inner sides of the bolt heads 19, 19 engage recesses 20, 20 in the block 10 so as to support such block. A gasket 21 between the blocks 10 and 1l serves to prevent any lubricant from leaking downward between the block 10 and the disc 6 onto the felt or glass. The periphery of the block 11 rests upon the shoulder 22 formed around the inner edge of the disc 6. Practically all the wear upon the runner block occurs at the bearing with the ball 5 so that the making of the blocks 10 and l1 removable and replaceable involves a substantial economy as the cost of renewing these parts is only a small part of the total cost of the runner block. The use of the block 10 as a clamping means also involves a considerable economy as to the felt used since the sheet 8 may be with safety worn much thinner when held at both its inner and outer edges than when held only at its outer edge as has been heretofore the practice.

In the modication shown in Fig. 3, the construction approximates that of Figs. 1 and 2 except that the lower block 23 does not act as a clamping means for the felt 24 and instead of being held by the bolts 25, 25 is supported upon an annular shoulder 26, a gasket 27 being interposed between such shoulder and the shoulder 28 at the lower end of the block 29, The heads of the bolts 25, 25 lie in slots 30, 30 in the disc 31 and serve to hold the block 29 in posit-ion. This construction has the same advantage as the con struction of Figs. 1 and 2 in the matter of the replacement of the parts 23 and 29 while still retaining the disc for use.

What I claim is:

In combination in a polishing block, a circular disc having an opening through its central portion, a spindle having a ball head, a felt sheet tting against one face of the disc and having its outer edges releasably secured to the periphery of the disc, the central portion of said sheet being cut away with the edges at such central portion turned up into the opening through the disc, a block fitting Yinto the opening and engaging said turned up edges, said block having a recess on its upper side for receiving said head, a second block above said block through which said spindle extends, provided With a recess engaging the upper portion of said head, and releasable means for securing both blocks in fixed position with respect to said disc.

ROBERT A. MILLER. 

